The present invention relates generally to a microwave coupler formed from a material with an alpha-rhombohedral-boron-derivative structure for effectively converting microwave energy into heat and more particularly to to a method for heating material in a microwave furnace by employing such a coupler.
Microwave energy has been receiving considerable interest as the heating mechanism for various metallurgical procedures especially those involving materials of high purity. In order for microwave energy to be considered a viable heating process in such procedures, the material being heated should possess microwave coupling properties, or a crucible or other form of susceptor having microwave coupling properties should be appropriately positioned in the microwave flux field to provide the coupling for heating the material undergoing the metallurgical procedure.
It was previously found that uranium oxide provided good coupling properties with microwave energy as reported in the publication "Heating of Uranium Oxides in a Microwave Oven" by Paul A. Haas, American Ceramic Bulletin, Vol. 58, No. 9 (1979). However, due to the potentially adverse reactions between uranium oxide and the materials to be heated in the microwave oven or furnace a selection of a material exhibiting greater inertness toward such reactions is needed.